What is a thermometer? Name some thermometers and their principles on which they work?
Thermometer is an instrument used for measuring the temperature.
The different types of thermometers are:
(i) Mercury thermometer: It is based on the principle that substance expands on heating.
(ii) Gas thermometer: It is based on Regnault’s law which states that at constant volume, the pressure of gas varies directly with temperature. Specific heat of gas is constant for all values of the pressure of gas.
(iii) Resistance thermometer: It is based on the fact that resistance of conductor increases with the increase in temperature.
(iv) Thermoelectric thermometer: It is based on Seeback effect.
The Seebeck effect is a phenomenon in which a temperature difference between two dissimilar electrical conductors or semiconductors produces a voltage difference between the two substances.
